Implement polymorphic inlining.

For example, before:
HInvokeVirtual

After:
If (receiver == Foo) {
  // inlined code.
} else if (receiver == Bar) {
  // inlined code
} else {
  // HInvokeVirtual or HDeoptimize(receiver != Baz)
}

Change-Id: I5ce305aef8f39f8294bf2b2bcfe60e0dddcfdbec

1 files changed, 50 insertions, 15 deletions

diff --git a/compiler/optimizing/nodes.cc b/compiler/optimizing/nodes.cc
index 27015c0ac6..95d0af539d 100644
--- a/compiler/optimizing/nodes.cc
+++ b/compiler/optimizing/nodes.cc
@@ -1386,7 +1386,38 @@ HBasicBlock* HBasicBlock::SplitCatchBlockAfterMoveException() {
   }
 }
 
-HBasicBlock* HBasicBlock::SplitAfter(HInstruction* cursor) {
+HBasicBlock* HBasicBlock::SplitBeforeForInlining(HInstruction* cursor) {
+  DCHECK_EQ(cursor->GetBlock(), this);
+
+  HBasicBlock* new_block = new (GetGraph()->GetArena()) HBasicBlock(GetGraph(),
+                                                                    cursor->GetDexPc());
+  new_block->instructions_.first_instruction_ = cursor;
+  new_block->instructions_.last_instruction_ = instructions_.last_instruction_;
+  instructions_.last_instruction_ = cursor->previous_;
+  if (cursor->previous_ == nullptr) {
+    instructions_.first_instruction_ = nullptr;
+  } else {
+    cursor->previous_->next_ = nullptr;
+    cursor->previous_ = nullptr;
+  }
+
+  new_block->instructions_.SetBlockOfInstructions(new_block);
+
+  for (HBasicBlock* successor : GetSuccessors()) {
+    new_block->successors_.push_back(successor);
+    successor->predecessors_[successor->GetPredecessorIndexOf(this)] = new_block;
+  }
+  successors_.clear();
+
+  for (HBasicBlock* dominated : GetDominatedBlocks()) {
+    dominated->dominator_ = new_block;
+    new_block->dominated_blocks_.push_back(dominated);
+  }
+  dominated_blocks_.clear();
+  return new_block;
+}
+
+HBasicBlock* HBasicBlock::SplitAfterForInlining(HInstruction* cursor) {
   DCHECK(!cursor->IsControlFlow());
   DCHECK_NE(instructions_.last_instruction_, cursor);
   DCHECK_EQ(cursor->GetBlock(), this);
@@ -1539,6 +1570,20 @@ void HInstructionList::AddAfter(HInstruction* cursor, const HInstructionList& in
   }
 }
 
+void HInstructionList::AddBefore(HInstruction* cursor, const HInstructionList& instruction_list) {
+  DCHECK(Contains(cursor));
+  if (!instruction_list.IsEmpty()) {
+    if (cursor == first_instruction_) {
+      first_instruction_ = instruction_list.first_instruction_;
+    } else {
+      cursor->previous_->next_ = instruction_list.first_instruction_;
+    }
+    instruction_list.last_instruction_->next_ = cursor;
+    instruction_list.first_instruction_->previous_ = cursor->previous_;
+    cursor->previous_ = instruction_list.last_instruction_;
+  }
+}
+
 void HInstructionList::Add(const HInstructionList& instruction_list) {
   if (IsEmpty()) {
     first_instruction_ = instruction_list.first_instruction_;
@@ -1781,18 +1826,6 @@ void HBasicBlock::ReplaceWith(HBasicBlock* other) {
   graph_ = nullptr;
 }
 
-// Create space in `blocks` for adding `number_of_new_blocks` entries
-// starting at location `at`. Blocks after `at` are moved accordingly.
-static void MakeRoomFor(ArenaVector<HBasicBlock*>* blocks,
-                        size_t number_of_new_blocks,
-                        size_t after) {
-  DCHECK_LT(after, blocks->size());
-  size_t old_size = blocks->size();
-  size_t new_size = old_size + number_of_new_blocks;
-  blocks->resize(new_size);
-  std::copy_backward(blocks->begin() + after + 1u, blocks->begin() + old_size, blocks->end());
-}
-
 void HGraph::DeleteDeadEmptyBlock(HBasicBlock* block) {
   DCHECK_EQ(block->GetGraph(), this);
   DCHECK(block->GetSuccessors().empty());
@@ -1846,7 +1879,8 @@ HInstruction* HGraph::InlineInto(HGraph* outer_graph, HInvoke* invoke) {
     DCHECK(!body->IsInLoop());
     HInstruction* last = body->GetLastInstruction();
 
-    invoke->GetBlock()->instructions_.AddAfter(invoke, body->GetInstructions());
+    // Note that we add instructions before the invoke only to simplify polymorphic inlining.
+    invoke->GetBlock()->instructions_.AddBefore(invoke, body->GetInstructions());
     body->GetInstructions().SetBlockOfInstructions(invoke->GetBlock());
 
     // Replace the invoke with the return value of the inlined graph.
@@ -1864,7 +1898,8 @@ HInstruction* HGraph::InlineInto(HGraph* outer_graph, HInvoke* invoke) {
     // with the second half.
     ArenaAllocator* allocator = outer_graph->GetArena();
     HBasicBlock* at = invoke->GetBlock();
-    HBasicBlock* to = at->SplitAfter(invoke);
+    // Note that we split before the invoke only to simplify polymorphic inlining.
+    HBasicBlock* to = at->SplitBeforeForInlining(invoke);
 
     HBasicBlock* first = entry_block_->GetSuccessors()[0];
     DCHECK(!first->IsInLoop());